1. Field of the Invention
The present invention relates to a thermally insulated housing for configuring the body of a cooling storage unit and the like, and a manufacturing method thereof.
2. Description of the Prior Art
There is a known example of a thermally insulated housing for configuring the body of a refrigerator described in Japanese Laid-Open Patent No. 6-300429. This example has an outer shell constituted by including an inner case housed at a predetermined interval within an outer case. Assembling multiple panels together forms the cases. The outer shell is then completed by charging foam insulation between the inner and outer cases in the state of having the cases set in a foaming jig.
In the situation of a large-size refrigerator for business or professional use, for example, the back surface in particular of the outer case may have a relatively large surface area. Therefore, there is a known refrigerator having a back surface formed by joining two panels together via mutually overlapping edges. As for a method of sealing the joint between both of the panels, a sponge is sandwiched between the overlapping edges of the panels and the assembly is riveted at appropriate intervals.
However, according to this conventional method, the work is troublesome because it is necessary to affix the sponge and to further rivet the assembly. In addition, the sponge may not be sufficiently compressed at locations distant from a riveted position. Therefore, there is a possibility of absorbing the liquid foaming agent when the foam is charged. This could have the opposite effect of widening the gap between the joint due to secondary foaming and the like.